Abstract

In this paper, we report new constraints on flavor-changing nonstandard neutrino interactions from the MINOS long-baseline experiment using ν e and ν¯ e appearance candidate events from predominantly ν μ and ν¯ μ beams. We used a statistical selection algorithm to separate ν e candidates from background events, enabling an analysis of the combined MINOS neutrino and antineutrino data. Finally, we observe no deviations from standard neutrino mixing, and thus place constraints on the nonstandard interaction matter effect, |ϵ eτ|, and phase, (δ CP + δ eτ), using a 30-bin likelihood fit.

We report on a new analysis of neutrino oscillations in MINOS using the complete set of accelerator and atmospheric data. The analysis combines themore » $$\nu_{\mu}$$ disappearance and $$\nu_{e}$$ appearance data using the three-flavor formalism. We measure $$|\Delta m^{2}_{32}|=[2.28-2.46]\times10^{-3}\mbox{\,eV}^{2}$$ (68% C.L.) and $$\sin^{2}\theta_{23}=0.35-0.65$$ (90% C.L.) in the normal hierarchy, and $$|\Delta m^{2}_{32}|=[2.32-2.53]\times10^{-3}\mbox{\,eV}^{2}$$ (68% C.L.) and $$\sin^{2}\theta_{23}=0.34-0.67$$ (90% C.L.) in the inverted hierarchy. The data also constrain $$\delta_{CP}$$, the $$\theta_{23}$$ octant degeneracy and the mass hierarchy; we disfavor 36% (11%) of this three-parameter space at 68% (90%) C.L.« less

We present a search for the rare leptonic decays B+ → e+ν and B+ → μ+ν, using the full *(4S) data sample of 772 × 106 B ¯B pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. One of the B mesons from the *(4S) → B ¯B decay is fully reconstructed in a hadronic mode while the recoiling side is analyzed for the signal decay. We find no evidence of a signal in any of the decay modes. Upper limits of the corresponding branching fractions are determined as B(B+ → e+ν) < 3.4 × 10-6 andmore » B(B+ →μ+ν) < 2.7 × 10-6 at 90% confidence level.« less